[llvm] Allow Specifying SGMasks for Inline Asm (PR #155491)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> Instead of this, we could add `__builtin_sched_group_barrier_override_sgmask()` with the semantics that a nonzero argument will override the sgmask for any instructions found prior to it. A call with 0 could clear the custom mask. That way, we're both giving users more control and not directly adding any code to support inline assembly.

All of these built-ins are a hack, and that's adding a hack on top of the hack. All of this stuff is a development resource sink we have to maintain forever and it's not worth it. 

Did you try just interpreting inline asm as matching all classes of instructions, or filtering based on whether there are VGPR or SGPR operands?



https://github.com/llvm/llvm-project/pull/155491